C8051F709-GQR Silicon Labs, C8051F709-GQR Datasheet - Page 150

• Manufacturer Part Number: C8051F709-GQR
• Description: 8-bit Microcontrollers - MCU 8kB 32B EEPROM Cap Sense
• Manufacturer: Silicon Labs

Specifications of C8051F709-GQR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F70x/71x
unlocked pages, and user firmware executing on locked pages. Table 22.1 summarizes the Flash security
features of the C8051F70x/71x devices.
22.4. Flash Write and Erase Guidelines
Any system which contains routines which write or erase Flash memory from software involves some risk
that the write or erase routines will execute unintentionally if the CPU is operating outside its specified
operating range of VDD, system clock frequency, or temperature. This accidental execution of Flash modi-
fying code can result in alteration of Flash memory contents causing a system failure that is only recover-
able by re-Flashing the code in the device.
To help prevent the accidental modification of Flash by firmware, the VDD Monitor must be enabled and
enabled as a reset source on C8051F70x/71x devices for the Flash to be successfully modified. If either
the VDD Monitor or the VDD Monitor reset source is not enabled, a Flash Error Device Reset will be
generated when the firmware attempts to modify the Flash.
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Read, Write or Erase unlocked pages
(except page with Lock Byte)
Read, Write or Erase locked pages
(except page with Lock Byte)
Read or Write page containing Lock Byte
(if no pages are locked)
Read or Write page containing Lock Byte
(if any page is locked)
Read contents of Lock Byte
(if no pages are locked)
Read contents of Lock Byte
(if any page is locked)
Erase page containing Lock Byte
(if no pages are locked)
Erase page containing Lock Byte - Unlock all pages
(if any page is locked)
Lock additional pages
(change '1's to '0's in the Lock Byte)
Unlock individual pages
(change '0's to '1's in the Lock Byte)
Read, Write or Erase Reserved Area
C2DE - C2 Device Erase (Erases all Flash pages including the page containing the Lock Byte)
FEDR - Not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is '1' after reset)
- All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset).
- Locking any Flash page also locks the page containing the Lock Byte.
- Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase.
- If user code writes to the Lock Byte, the Lock does not take effect until the next device reset.
Action
Table 22.1. Flash Security Summary
Rev. 1.0
Permitted
Not Permitted FEDR
Permitted
Not Permitted FEDR
Permitted
Not Permitted FEDR
Permitted
Only by C2DE FEDR
Not Permitted FEDR
Not Permitted FEDR
Not Permitted FEDR
C2 Debug
Interface
Permitted
Permitted
Permitted
FEDR
an unlocked page a locked page
User Firmware executing from:
Permitted
Permitted
Permitted
Permitted
Permitted
Permitted
FEDR
FEDR
FEDR
FEDR
FEDR